580 SYSTEMATIC PALEONTOLOGY 



Gryphceostrea lateralis Conrad, 1868, Cook's Geol. of New Jersey, p. 724. 

 " Ostrea lateralis Nilsson " Coquand, 1869, Mon. Genre Ostrea, p. 96, pi. xxx, 



fig. 10. (Not Ostrea vomer d'Orbigny, 1850, Coquand, Mon. Genre 



Ostrea, p. 39, pi. xvi, figs. 13-15. = 0. 'convexa Say.) 



Gryphceostrea vomer Meek, 1876, Kept. U. S. Geol. Survey, Terr., vol. ix, p. 11. 

 Ostrea vomer White, 1884, 4th Ann. Kept. U. S. Geol. Survey, p. 302, pi. xlviii, 



figs. 8-10. 

 Gryphceostrea vomer Whitfield, 1885, Mon. U. S. Geol. Survey, vol. ix, p. 



195, pi. xxvi, figs. 11, 12. 



Ostrea sp. Clark, 1895, Johns Hopkins Univ. Circ., vol. xv, p. 6. 

 Ostrea sp. Clark, 1896, Bull. 141, U. S. Geol. Survey, p. 88, pi. xxxix, figs. 



3a-3c. 



Ostrea subeversa Clark, 1896, Bull. 141, U. S. Geol. Survey, p. 93. 

 Ostrea (Gryphceostrea) subeversa Ball, 1898, Trans. Wagner Free Inst. Sci., 



vol. iii, pt. iv, p. 681. 

 Ostrea (Gryphceostrea) vomer Clark, 1901, Md. Geol. Survey, Eocene, p. 193, 



pi. 1, figs. 1-5. 

 Ostrea (Gryphceostrea) vomer Johnson, 1905, Proc. Acad. Nat. Sci., Phila., 



p. 11. 

 Gryphceostrea vomer, Weller, 1907, Geol. Survey of New Jersey, Pal., vol. 



iv, p. 455, pi. xliv, figs. 7-11. (Exclude fig. 6, broken valve of Gryphcea 



vesicularis) . 



Description. " Shell subrhomboidal ; upper valve small, thin, slightly 

 concave ; lower valve convex, obscurely lobed, the lobed margin obliquely 

 produced from the hinge ; a wrinkled groove each side of the latter ; beak 

 pointed, curved obliquely inwards ; umbo prominent." Morton, 1828. 



Type Locality. New Egypt, New Jersey. 



Shell of moderate size, elongate, rudely ovate or elliptical, strongly 

 inequivalve ; attached left valve strongly convex, often irregular in outline 

 over the area of attachment in the umbonal region ; umbones inflated, tips 

 prosogyrate and acutely pointed, when not flattened against the sup- 

 porting surface; anterior and posterior dorsal margins of perfect and 

 typically developed individuals produced into long, slender, auricular 

 extensions somewhat similar to those of Gryphcea convexa Say. External 

 surface of left valve smooth excepting for growth striations, right cover- 

 valve regularly subovate, flattened, often a little sinuous and with a 

 slight forward twist in the flattened umbonal region; external surface 

 sculptured with conspicuous, fine-edged concentric laminas, five to eleven 

 in number, regularly spaced, parallel to the outer margin and delimiting 

 the outline of the shell during former stages of growth ; hinge area small, 



